This application is based upon and claims the benefit of priority from, the prior Japanese Patent Application No. 2001-243083, field Aug. 10, 2001, the entire contents of which are incorporated herein by reference.
The present invention relates to a water soluble bactericide and a producing method thereof.
The present inventors have long been conducting researches in sterilization using ozone or ozone water. It has been proved through various researches that the strong oxidation ability of ozone is very useful for sterilization. However, depending on a handling manner, ozone is harmful even for the human body and possibly destroys not only bacteria but also cells of the human body, and thus, careful handling is required therefor.
According to the general ozone acquiring method, gas phase oxygen from an oxygen bomb is caused to pass through an ozonizer generating silent discharge under high tension alternating current, thereby to bring material oxygen in contact with the silent discharge field so as to ozonize a portion of the material oxygen. Since the several ten kilovolt high tension alternating current is used for obtaining ozone, a qualified operator is required for operating the ozonizer. Further, since the obtained ozone is in gas phase, handling thereof is difficult so that a special attention is necessary for avoiding any possibility of leakage. Moreover, the thus obtained ozone has a very short half life and thus can not be preserved. Accordingly, it is necessary to bring in an ozonizer equipped with a large-size high voltage power supply device to a using place.
Recently, attention has been paid to liquid phase ozone rather than the foregoing gas phase ozone. This liquid phase ozone is obtained such that a substance having an ozone producing catalyst function, such as gold or platinum, is used as a material of electrodes for electrolyzing water, a portion of oxygen produced through. electrolysis of water is ozonized and the produced ozone is immediately dissolved in water. Therefore, even if this liquid phase ozone leaks, dispersion thereof is limited and thus it is relatively safe. Further, since only ten and several volt dc voltage is sufficient for the electrolysis, the device can be reduced in size, and thus there have already been available an ozone water hand washing apparatus and the like having a high bactericidal efficiency.
However, although using the strong oxidation ability of ozone directly for sterilization as described above is well worth notice, there has been a big question about the safety thereof depending on how to handle it. There has also been a problem in view of the preservability thereof. In general, it is necessary to produce ozone at a using place, which is a main cause of preventing sterilization by ozone from spreading.
The present invention has been made for solving the foregoing problems. Attention has been paid to the fact that an oxidation effect of ozone on organic matter has a tendency to selectively cleave a specific molecule link portion. Accordingly, researches have been conducted to obtain a substance having a bactericidal ability through oxidation by ozone (hereinafter referred to as xe2x80x9cozone-oxidationxe2x80x9d), not using the oxidation ability of ozone directly for sterilization.
Therefore, it is an object of the present invention to provide a water soluble bactericide through ozone-oxidation, which can maintain the oxidation ability over a long term.
According to the first aspect of the present invention, there is provided a water soluble bactericide obtained by oxidizing glycerin with ozone, i.e. by ozone-oxidizing glycerin.
Therefore, hydroxyl group (xe2x80x94OH) of glycerin is selectively oxidized by ozone, so that ozone oxides having oxidation abilities as shown in FIGS. 6 and 7 are produced.
According to the second aspect of the present invention, there is provided a method of producing a water soluble bactericide, wherein liquid phase glycerin and gas phase ozone are brought into gas-liquid contact with each other. In a preferred embodiment, the gas phase ozone is obtained by ozonizing oxygen through contact between oxygen and a silent discharge field.
Therefore, glycerin can be oxidized by ozone (hereinafter referred to as xe2x80x9cozone-oxidizedxe2x80x9d) by simply aerating liquid phase glycerin with gas phase ozone. Ozone has a strong oxidation ability, and thus, heating, agitation or the like is not necessary. Rather than a rapid reaction, a gradual reaction is desirable for the selective oxidation. Since a material of ozone is limited to oxygen, there is no entering of nitrogen oxide which would otherwise enter when air is used as a material, production of a substance associated with nitrogen oxide, which would be otherwise caused following ozone-oxidation, can be prevented.
According to the third aspect of the present invention, there is provided method of producing a water soluble bactericide, wherein a 0.1 to 20% glycerin aqueous solution and gas phase ozone are brought into gas-liquid contact with each other. In a preferred embodiment, the gas phase ozone is obtained by ozonizing oxygen through contact between oxygen and a silent discharge field.
Therefore, since glycerin is in the form of an aqueous solution, the viscosity of glycerin is lowered. Accordingly, the gas-liquid contact can be performed efficiently to achieve ozone-oxidation in a relatively short time. The obtained water soluble bactericide differs in oxidation ability and its half life depending on a glycerin concentration. Thus, the oxidation ability and its half life can be set according to the purpose of its use.
According to the fourth aspect of the present invention, there is provided a method of producing a water soluble bactericide, wherein a glycerin aqueous solution is electrolyzed. In a preferred embodiment, the glycerin aqueous solution is a 0.1 to 20% glycerin aqueous solution. Further, in a preferred embodiment, the glycerin aqueous solution is electrolyzed in an electrolytic device wherein dc voltage is applied across electrodes. Further, in a preferred embodiment, a substance having an ozone producing catalyst function, such as gold, platinum or titanium, is used as a material of electrodes.
Therefore, water is electrolyzed to produce oxygen and a portion thereof is ozonized by the catalyst function of the electrodes, so that ozone thus produced oxidizes glycerin directly or after dissolving in water. In the foregoing method according to the second aspect of the present invention, only the saturation ozone amount which can dissolve in water is utilized. On the other hand, in the method according to the fourth aspect of the present invention, the ozone-oxidation can be theoretically continued until all the added water is electrolyzed.